500 Watt End Fed 36:1 Transformer Kit

OCFMasters spent two years delving into the ins and outs of End Fed antennas. Throughout that time, we discovered that most End Fed antenna transformers used higher impedance transformations than necessary and were wound in a way that limited the high frequency response of the transformer.

The transformer secondary is wound first with 12 turns of the #18 enamel wire using the tie wraps to hold the ends if needed. Next, the 2-turn #18 primary is wound over the center of the secondary and the 56pF capacitor and wires are soldered to a SO-239 coax connector.

If you are using a wire counterpoise connect one end of the secondary to the long wire and the other side to the counterpoise (13' 2" for 80M and 7' for 40M) and attach a 1:1Balun/Choke to the transformer. If you are using a coax counterpoise, connect one end of the secondary to the long wire and the other end to the ground/shield side of the connector and use 13' 2" coax for 80M or 7' for 40M to a 1:1 choke/Balun to make the outside of the shield be the counterpoise.

This transformer can handle 450 watts SSB, 350 watts CW and 200 watts Digital. It will deliver good performance from 80-10 Meters.

See our book, "Wire Antennas 160 meters to 70 cm: Concepts, Theory and On the Air" second edition, available on OCFmasters.com, Ham Radio Outlet or Amazon, for more details.